It is well known to catalyze the alkylation of aromatics with a variety of Lewis or Bronsted acid catalysts. Typical commercial catalysts include phosphoric acid/kieselguhr, aluminum halides, boron trifluoride, antimony chloride, stannic chloride, zinc chloride, onium poly(hydrogen fluoride), and hydrogen fluoride. Alkylation with lower molecular weight olefins, such as propylene, can be carried out in the liquid or vapor phase. For alkylations with higher olefins, such as C16 olefins, the alkylations are done in the liquid phase, usually in the presence of hydrogen fluoride. Alkylation of benzene with higher olefins is especially difficult, and requires hydrogen fluoride treatment. However, hydrogen fluoride is not environmentally attractive.
The use of the above listed acids is extremely corrosive, thus requiring special handling and equipment. Also, the use of these acids might involve environmental problems. Another problem is that the use of these acids can give less than desirable control on the precise chemical composition of the product produced. Thus, it would be preferable to use a safer, simpler catalyst, preferably in solid state. This simpler process would result in less capital investment, which would result in a less expensive product.
Solid crystalline aluminosilicate zeolite catalysts have been known to be effective for the alkylation of aromatics with olefins. Zeolitic materials which are useful as catalysts are usually inorganic crystalline materials that possess uniform pores with diameters in micropore range that is less than 20 angstroms. Zeolites occur naturally and may also be prepared synthetically. Synthetic zeolites include, for example, zeolites A, X, Y, L and mordenite. It is also possible to generate metaloaluminophosphates and metalosilicophosphates. Other materials, such as boron, gallium, iron or germanium, may also be used to replace the aluminum or silicon in the framework structure.
These zeolite catalyst materials are commercially available as fine crystalline powders for further modification to enhance their catalytic properties for particular applications. Processes for the further modification to enhance catalytic properties of the crystalline zeolite catalysts are well known in the art, such as forming the zeolite catalysts into shaped particles, exchanging the cations in the catalyst matrix, etc.
Forming the zeolite powders into shaped particles may be accomplished by forming a gel or paste of the catalyst powder with the addition of a suitable binder material such as a clay, an inorganic compound, or an organic compound and then extruding the gel or paste into the desired form. Zeolite powders may also be formed into particles without the use of a binder. Typical catalyst particles include extrudates whose cross sections are circular or embrace a plurality of arcuate lobes extending outwardly from the central portion of the catalyst particles.
One problem with catalyst particles used in fixed bed reactors is catalyst deactivation. In most hydrocarbon conversion processes, including alkylation, the primary catalyst deactivation is caused by coke formation. This catalyst deactivation is a serious problem in the use of zeolite catalysts for alkylation reactions. This deactivation problem is well known in the art and it is well understood that the deactivation mechanism can involve polymerization of the olefin into large molecular species that cannot diffuse out of the pores containing the active sites in the zeolitic material.
The use of zeolite catalysts for preparation of alkylated aromatic hydrocarbons is typically conducted by the catalytic alkylation of aromatic hydrocarbons with normal alpha olefins or branched-chain olefins, and optionally a promotor.
A number of patents have discussed processes for the preparation of zeolite catalysts and the further shaping and forming of the catalyst particles and extrudates with and without the use of binders. There are also a number of patents disclosing the use of zeolite catalysts for alkylation of aromatic hydrocarbons.
U.S. Pat. No. 3,094,383 discloses the preparation of synthetic zeolite materials which upon hydration yield a sorbent of controlled effective pore diameter and in which the sorbent and its zeolite precursor are provided directly in the form of an aggregate.
U.S. Pat. No. 3,119,660 discloses a process for making massive bodies or shapes of crystalline zeolites. The patent also discloses methods for the identification of the catalyst materials using X-ray powder diffraction patterns in conjunction with chemical analyses.
U.S. Pat. No. 3,288,716 discloses that the high “heavy content” of the alkylated aromatic product can be controlled during the alkylation step and has advantages over distilling the alkylated aromatic product to obtain the desired molecular weight.
U.S. Pat. Nos. 3,641,177 and 3,929,672 disclose the technique to remove sodium or other alkali metal ions from zeolite catalysts. The '177 patent also discloses that such removal of the sodium or other alkali metal ions activates the zeolite catalysts for the alkylation of aromatic hydrocarbons with olefins by liquid phase reaction.
U.S. Pat. Nos. 3,764,533, 4,259,193 and 5,112,506 disclose the “heavy alkylate” content influences neutral sulfonates and overbased sulfonates. In U.S. Pat. No. 5,112,506, the effect of molecular weight distribution or “heavy alkylate” is shown to influence the performance of both Neutral and HOB sulfonates and the di-alkylate content is shown to influence the rust performance of the corresponding sulfonate in U.S. Pat. No. 3,764,533. In U.S. Pat. No. 4,259,193, a mono-alkylate sulfonate is preferred. U.S. Pat. Nos. 3,288,716; 3,764,533; 4,259,193; and 5,112,506 are hereby incorporated by reference for all purposes.
U.S. Pat. No. 3,777,006 discloses the use of nucleating centers for the crystallization of crystalline aluminosilicate zeolites having a size in excess of 200 microns and characterized by high strength and excellent adsorptive properties.
U.S. Pat. No. 4,185,040 discloses the preparation of highly stable and active catalysts for the alkylation of aromatic hydrocarbons with C2–C4 olefins. The catalysts are acidic crystalline aluminosilicate zeolites which exhibit much improved deactivation rates.
U.S. Pat. No. 4,764,295 discloses a process for making non-foaming detergent-dispersant lubricating oil additives. The process further involves carbonation for making the products more basic.
U.S. Pat. No. 4,891,448 discloses a process for alkylation of polycyclic aromatic compounds in the presence of an acidic mordenite zeolite catalyst having a silica to alumina molar ratio of at least 15:1 to produce a mixture of substituted polycyclic aromatic compounds enriched in the para alkylated isomers.
U.S. Pat. No. 5,004,841 discloses a process for alkylation of polycyclic aromatic compounds in the presence of an acidic mordenite zeolite catalyst having a silica to alumina molar ratio of at least 15:1 to produce substituted polycyclic aromatic compounds enriched in the linear alkylated isomers.
U.S. Pat. No. 5,118,896 discloses an aromatic alkylation process comprising the steps of contacting a aromatic hydrocarbon feed with an alkylating agent under liquid phase alkylation conditions in the presence of a silica-containing large macropore, small particle size zeolite catalyst, the catalyst having a pore volume of about 0.25 to 0.50 cc/g in pores having a radius of 450 angstroms and a catalyst particle diameter of not more than 1/32 of an inch.
U.S. Pat. No. 5,175,135 discloses the use of an acidic mordenite zeolite catalyst for alkylation of aromatic compounds with an alkylating agent having from one carbon atom to eight carbon atoms to produce substituted aromatic compounds enriched in the linear alkylated isomers. The acidic mordenite catalyst is characterized by its silica to alumina molar ratio, its porosity and a Symmetry Index.
U.S. Pat. No. 5,191,135 discloses the process for making long-chain alkyl-substituted aromatic compounds from naphthalenes, the process comprising a zeolite alkylation catalyst in the presence of 0.5 to 3.0 weight percent water. The presence of water increases the selectivity for making mono-alkylated products.
U.S. Pat. No. 5,198,595 discloses a process for alkylation of benzene or substituted benzene in the presence of an acidic mordenite zeolite catalyst having a silica to alumina ratio of at least 160:1 and a Symmetry Index above about 1.0. A process for the preparation of the catalyst is also disclosed.
U.S. Pat. No. 5,243,116 discloses the production of alkylated benzenes by alkylation and/or transalkylation in the presence of an acidic mordenite zeolite catalyst having a silica to alumina molar ration of at least 30:1 and a specific crystalline structure determined by X-ray diffraction.
U.S. Pat. Nos. 5,240,889 and 5,324,877 disclose processes for the preparation of a catalyst composition having alkylation and/or transalkylation activity and wherein the catalyst composition contains greater than 3.5 weight percent water based on the total weight of the catalyst composition and the aromatic alkylation process using said catalyst composition and olefins containing 2 carbon atoms to 25 carbon atoms.
U.S. Pat. No. 5,453,553 discloses a process for the production of linear alkyl benzenes which process comprises co-feeding a mixture of benzene, linear olefins and molecular hydrogen in the presence of a zeolite catalyst containing a transition metal under alkylation condition such that the catalyst is not deactivated.
U.S. Pat. No. 5,922,922 discloses a process for isomerizing a normal alpha olefin in the presence of an acidic catalyst having a one-dimensional pore system, and then use of the isomerized olefin to alkylate aromatic hydrocarbons in the presence of a second acidic catalyst, which can be mordenite zeolite having a silica to alumina ratio of at least 40 to 1.
U.S. Pat. No. 5,939,594 discloses the preparation of a superalkalinized alkylaryl sulfonate of alkaline earth metal. The alkyl group of the alkylaryl sulfonate contains between 14 to 40 carbon atoms and the aryl sulfonate radical of alkaline earth metal is fixed in a molar proportion comprised between 0 and 13% in positions 1 or 2 of the linear alkyl chain.
U.S. Pat. No. 6,031,144 discloses a process for reducing the residual olefin content of an alkylation reaction product by removing at least a portion of the non-alkylated single-ring aromatic hydrocarbon and then reacting the remaining alkylation reaction product in the presence of an acidic catalyst such as a molecular sieve or clay.
U.S. Pat. No. 6,337,310 discloses the preparation of alkylbenzene from preisomerized normal alpha olefins for making low overbased and high overbased sulfonates having a total base number between 3 and 500. The process uses HF as catalyst or a solid acidic alkylation catalyst, such as a zeolite having an average pore size of at least 6 angstroms.
U.S. Pat. No. 6,525,234 discloses a process for alkylating aromatic using a porous crystalline material, e.g., MCM-22 and in situ regenerating the catalyst by use of a polar compound having a dipole moment of at least 0.05 Debyes. It is known that most solid acid catalysts produce high 2-aryl attachment when alkylating with alpha-olefins. See S. Sivasanker, A. Thangaraj, “Distribution of Isomers in the Alkylation of Benzene with Long-Chain Olefins over Solid Acid Catalysts,” Journal of Catalysis, 138, 386–390 (1992). This is especially true for mordenite zeolite.
Two general treatises on zeolite are: Handbook of Molecular Sieves by Rosemarie Szostak (Van Nostrand Reinhold, New York 1992) and Molecular Sieves: Principles of Synthesis and Identification, 2nd Edition, by Rosemarie Szostak (Chapman and Hall, London, UK 1999).